The entries within A Guide to the Star Wars Universe are divided into a series of categorized lists to help readers find specific names or terms. The entries within the main body of the book are alphabetized with no further categorization. They can be short and to the point as in the case of the entry for "hydrospanner." The longest entries within A Guide to the Star Wars Universe are about a page and a half long. The subjects of these long entries are usually devoted to descriptions of main characters and battles.

Every entry is followed by a series of codes which tell the reader where the information contained in the entry is drawn from and a list of source materials and their individual codes are provided at the front of the book. Where appropriate, an entry will direct readers to look at other entries relevant to the subject that it covers. This is the sole function of approximately 67 entries within the book. 43 entries are accompanied by a picture of their subject and 20 entries include a pronunciation guide. The entry for the "Behavioral Circuitry Matrix" includes a diagram.

A Guide to the Star Wars Universe was written at a relatively early time in the history of Star Wars. In contrast to more recent reference books that have been presented as in-universe works, certain entries within A Guide to the Star Wars Universe contain references to real-world elements.

For example, Orron III is described as "an Earthlike agricultural world." However, the most common examples of this occur within the entries for the Rebel pilots at the Battle of Yavin, which point out differences between the novelization and the film in the pilots' com designations. Additionally, Luke Skywalker's entry states: "(The second of three trilogies in the saga known as Star Wars chronicles the events in galactic history revolving around Luke Skywalker. The second trilogy is comprised of three stories: 'A New Hope,' 'The Empire Strikes Back,' and 'Return of the Jedi.')"

After Velasco had turned in the manuscript of A Guide to the Star Wars Universe, Judy-Lynn del Rey asked Brian Daley to review it and correct any errors that he had found. Daley would later claim in an interview conducted by fan Alex Newborn that he had filled up two to three pages with errors that he had found in the manuscript relating to the movies, his novels and a number of other sources. In addition to this, Velasco had related subjects that were never intended to be such. For example, Daley had never intended the character Squeak to be a Tin-Tin Dwarf.[1]

Though he acknowledged that A Guide to the Star Wars Universe was not perfect, Abel G. Peña would salute Velasco for what he considered to be a "corusca gem in the rough."[2] In an essay about the first edition of A Guide to the Star Wars Universe, Peña cited the diagram of the Behavioral Circuitry Matrix and other examples in the book as reasons for why Velasco should be considered "the father of the ret-con in the Star Wars Universe" and "Star Wars' very first fanboy author." [3]

It appears that the only continuity errors that made it into the published edition of A Guide to the Star Wars Universe had to do with the physical descriptions of the bounty huntersBossk and Zuckuss. This may indicate a reliance upon the novelization of The Empire Strikes Back for certain details. In addition, a few entries were misspelled (e.g. "Galandro" instead of "Gallandro," and "Sabador" instead of "Sabodor").

It is also questionable whether some entries should have been entries at all, as they were either standard English words with no different meaning in the Star Wars universe (e.g. "erg"), or phrases consisting of words that in combination carry no meaning beyond that implied by standard English construction (e.g. "external audio pickup").

The book categorizes each entry into one or more of the eleven broad categories below. The one term that has an entry in the main body but is not categorized in the lists is medipak. The synonymous term medikit is in the category lists, followed by the parenthetical "(see ref.)" Although many entries in the main body are merely pointers to other entries, this is the only one so marked in the category lists.